1. Technical Field
The present invention relates to a dust collecting apparatus, and more particularly, to a chalk-dust collecting apparatus for blackboard erasers with an improved dust-collecting bag.
2. Description of Related Art
A conventional chalk-dust collecting apparatus, as shown in FIG. 12, typically comprises a suction motor C presenting suction force to draw chalk dust into a dust-collecting bag G from an upper air inlet I located at an upper lid J of the housing A. As the dust-collecting bag G is typically designed with a wide opening, chalk dust drawn thereto and retained therein can easily diffuse or escape therefrom and disadvantageously results in contamination and pollution of the surrounding area.
Besides, as there is no any filterable component particularly provided for the suction motor C at the front end air entrance F, escaped or diffused dust coming fro the dust-collecting bag G can be drawn directly into the suction motor C and cause significant mechanical damage. Even worse, in the occasion the dust-collecting bag G is missed during assembly, and the apparatus is nevertheless operated, mass dust comes along with air flow can totally destroy the suction motor C.